Cannon feed unit



April 2, 1946. E. J. MEYER CANNON FEED UNIT Filed May 19, 1945 3 Sheets-Sheet l INVENTOR EDWARD J. MEYER ATTORNEY April 2, 1946. E. J. MEYER CANNON FEED UNIT Filed May 19, 1943 3 Sheets-Sheet 2 .k llll I FL F no 1 ENVENTOR EDWARD J. MEYER ATTORNEY April 2, i946, E; J. MEYER 2,397,501

CANNON FEED UNIT Filed May 19, 1943 3 Sheets-Sheet 3 67 ATTORNEY Patented Apr. 2, 1946 our-rs: sr

CAN NON FEED UNIT .Edward :J. Meyer, Normandy, Mo., assignor to 'Curtiss-Wright Corporation, a corporation of Delaware Application May 19, 1943,:Serial No; 487,828

2 Claims.

This'invention'relates to feed units for automatic guns or cannon, and more particularly'to feed :units such-as used with guns mountable in military airplanes.

*Heretofore, feed-units used with "the 120 "mm. cannon-or gun, such asareinstalled@in'airplanes, has been of complicated construction, of large size requiring considerable head space within the airplane wing, difficultto re-arrangeso that shlls'couldbe de'livered'to it from one side or the other without actually having :to remount the gun to align the feed unit in the proper direction, andtheguncould not be charged by the unit while inthe air 'beyond a limited number of charging operations. The charging of the gun was determined wholly upon the stored energy in a spring "whichhadtto the manually tightened on the ground beforetheta'ke-off and space was required in the 'wing "structure of the airplane in order to permititlre insertion of a wrench to tighten .up'th'e spring. .Asi'soon as the spring became unwound, charging of the gun in the air became impossible. In connection with the use of thespring, there wasprovideda' clutch mechanism consisting :of a considerable number of parts arrangedto receive considerable wear and contributing thereby "to an early'failure of the unit.

It is the principal object of the present invention to provide a feed unit for automatic guns which is of :less complicated construction, less bulky, and which is more adaptable forinstallation in an airplane.

'It is another object of the present invention to provide a feed unit :for automatic guns which is reversible for "conditioning 'the same "to receive shell from either the right side or "the left :side of the gun and without thereby having to remount the gun in "the airplane.

It is still another object of the invention to provide, in connection with an automatic .feed unit of the type adapted normally to be operated by the recoil mechanism of the gun, an arrangement for stepping shells through the unit independently :of recoil action of the gun and without the necessity of firing a single shell, and wherein this stepping action may .be done throughout an indefinite length of the ammunition belt, and wherein the unit to accomplish this operation need not have to be re-set or wound on the ground with :a special tool prior to each flight.

According to the present invention, there has been provided a. feed unit which is of simple construction, adapted to be operated by the recoil mechanism of the gun; and with parts thereof so arranged that they may be readily assembled to-receivethe shell from either-side of the-gun. The unit has a pawl' carrier with-pawls thereon adapted toengage oneshell'at -a-time' of an ammunition belt; threaded into'atransverse opening of the unit. These pawls serve -to advance the shells through the unit to a depositopening therein from which each shell is taken by-thegun bolt. The pawl carrier isconne'cted to therecoil mechanism to be operated by the same. The connection is provided with an over-travel lost motion slot whereby, regardless of -any slight variance in the'amount of recoil action or length of stroke of the same, as predetermined by "the fire power of the shell which is fired, the=carrier with its pawl wil1=on1y be advanced the same amount each time. -Within the-transverse opening there are-providedstripper elements arranged to separate the shells from the shellretainers or clipsgto depress the shells-down-into the central opening of the unit, and-to deliver-the retainers in an orderly manner-to-the opposite side of the unit for ejection therefrom. 'In-or-der that the unit may be operated at any time independently of the recoil-mechanism-for the purpose of providing a shell with which to charge the gun, there is provided, in the connection between thecarrier and'the recoil mechanism,-a fluidmotor or fluid expansible link which, when operated, will lengthen the connection to operate the pawl carrier. This fluid motor is 'constructedso that, without the fluid pressure therein, the fluid motor serves asa rigid link in the-connection andreceives the regular impulseiromthe recoil mechanism. Withsuch a fluid-motor link, theentire ammunition belt'can be advanced through the feed unit. This fluid motor is connected to a fluid system which is ordinarily used for the operation of the hydraulic charging cylinder of the gun so that, as the charging cylinder is operated, the fluid motor will-hooperatedsimultaneously therewith. As the shell which is in the gun is extracted'by the charging cylinder, the feed unit will simultaneously be operated to ad- Vance the shell through the same so asto thereby provide a shell inthe position so as to recharge thegun with the returnstroke of thegun charging cylinder.

The entire unit is so constructed that it requires only minimum head space 'and by simply reversing certain parts of the unit so that its entrance opening is on the opposite side and making slight changes in the'connec'ting or the connectionlinks with the recoil mechanism, the unit can be reversed so as to receive shells from the opposite side of the unit. This is all done without the need of additional parts and without the necessity type that it is mountable upon the carrier along with the pawl and such that it extends fiat-wise thereby taking up little vertical head space.

For other objects and for a better understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a plan view of the feed unit and of that portion of the gun on which it is mounted.

Fig. 2 is a side view of the feed unit and the gun with an illustration of how the shells are delivered by the unit to the gun.

Fig. 3 is a side View of the opposite side of the unit and the gun.

Fig. 4 is an end view of the unit and the gun looking rearwardly from the front of the gun.

Fig. 5 is a sectional view, in elevation, of the unit, with further illustration of the advancement of the shells through the unit, the view being taken along the line 5-5 of Fig. l.

Fig. 6 is a similar sectional view of the unit but taken along the line 6 6 of Fig. 1.

Fig. '7 is an illustrative View, taken in section, and showing the manner in which the shells are led over the stripper elements and separated from their retainers or clips, and the delivery of the retainers to the opposite side of the guns.

or pawl carrier 29 on which. is pivotally mounted a longitudinally extending shaft 2|, on the opposite ends of which is respectively connected pawls 22 and 23. These pawls 22 and 23 extend downwardly through a top plate 24 bolted by bolts 25 to a base structure 26 which carriers the depending projection it. The connection of the pawl carrier 20 with the movable'stud H of the gun definite amount of movement and this movement Fig. 8 is a perspective View of one of the stripper I side at which the shells enter the unit.

Fig. is a more or less diagrammatic View of the hydraulic system for operating the gun charging cylinder and the fluid motor, with the fluid motor itself being shown in section.

Fig.'11 is a fragmentary view-of that part of the carrier operating connection having the overtravel slot and illustrating the principle of the operation of the slot. 7

Referring now particularly to Figs. 1, 2, 3, and 9, there is shown'a shell feed unit adapted to be mounted on a gun It having a recoil mechanism I l with a stud I'I rigidly mounted on such recoil mechanism and extending upwardly from the top of the gun. The recoil mechanism is of any'suitable type, and is adapted to be moved axially'of the gun in a rearward direction upon feed unit-I5 is rigidly attached to the non-recoiling part of the gun, it is evident that the stud I1 moves towards and away from the feed unit It each time the gun is fired.

On the feed unit l5 there is a depending projection i8 adapted to be seated in a shell opening IS in the top of the gun 16. When the unit is mounted on the gun, it is simply fitted so'that the depending projection 18 is fitted into the shell opening iii of the gun. The operating mechanism of the unit includes a laterally extending slide is made by a link 21 and a bell crank 28 pivoted on a pin 29 secured to the top plate 24 in such a manner that it can be removed and placed in another location on the top plate 24. On the slide or pawl carrier there is an upwardly extending pin 38) adapted to fit within an overtravel slot 3! on one arm 32 of the bell crank 28.

This slot 3| isof dog-leg shape and has a portion 33 adapted to receive the pin 38 when the pawl carrier is in its retracted position (Fig. l and the full-line position in Fig. 11) As the bell crank 28 is moved about the pivot pin 29, in a clockwise direction, the pin 39 travels along the portion 33 of the slot until it passes the ledge 34 and reaches the uppermost broken line position shown in Fig. 11. In this position, further clockwise rotation of the bell crank 23 and the pin 29 causes the pin to ride in the portion 35 of slot 3i without further motion of the pawl carrier 23. This arrangement will give to the slide only a is only suificient to retract the slide to a position where it is enabled to advance the shell one. step through the feed unit. The entire arrangement is thus so dimensioned and arranged that regardless of the amount of movement of the stud ll, the carrier 20 will be 'given only this definite amount of movement. The bell crank'armp32 always over-travels the carrier pin 30 at a predetermined point to which the carrier pin 38 and the carrier 29 have been advanced.

As seenmore clearly in Figs. 4, 5, 6, and 7, the

projection l8 provides a central opening 36 into which the shells are finally deposited priorto the same being taken from the unit by the gun bolt. On a lower edge of the projection it there are inwardly extending lips 31 which stop down order to retain the shell.

The depressing 0f the shell into the opening 33 is effected by springs 38 and 38a (Fig. 2) secured to the inner face of plate 24 and which engage the top of the shell to aid in forcing the same down into the opening 36 after it has been freed of its clips M by stripper elements 39 and 40 located within a transverse opening 42 between the base structure 26 and its cover plate 24. Into this transverse opening 42 the shells with their clips are delivered and these clips have lateral projections .3 which are directed respectively into grooves 44 in the sides of the stripper elements. The contact of the clip projection 43 with these stripper elements is first made with an inclined surface 45 by which they are caused to be forced upwardly into the more restricted part of the groove 44. At the same time that the clips 4| are forced upwardly and into the groove, the shells are forced downwardly due to action of a rounded or guiding'bottom face it or the strippers and finally separate from their clips. The clips ti continue through the stripper grooves 46 and are moved to the opposite side of the openin t2 and finally delivered out of the feed unit, Fig. 7. At all times the clips are restrained from becoming disconnected from each other and by being caused to travel along a definite path until they are finally discharged from the unit.

Upon recoil of the gun, the pawl carrier 26 is retracted (moved to the left in Fig. 1), carrying the pawls 22 and 23 with it. The advancement of shells through the unit is then eifected by the pawls 22 and 23, each of which, as shown particularly well in Figs. 5 and 6, has a concave forward face 49 adapted to fit one of several shells 50 so as to be thrusted by the pawl as the slide 26 is moved to the right from its recoiled position to. the position shown in Fig. 1. In order to maintain the pawls 22 and 23 in engagement with the shell 66, there is provided a, spring 5| adapted to extend through a diametrically extending slot 52 7' in the "shaft 2!. This spring 5| is of flat construction and has a plurality of fingers, all of which extend into the slot 52 of the shaft 2| at different locations along the same and the spring in its entirety is anchored to the top of the carrier by a clamping plate 53 retained on the carrier by bolts 54. It will thus be apparent that, by a spring of this design, maximum energy may be had for operation of the pawl without the same taking up great head space, which would tend to lengthen the over all height of the unit.

In order that the shells 56 be retained in the advance position within the transverse opening 42 and in order to allow the pawls to be retracted to engage a following shell, there is provided a holding pawl mechanism 55 including pivotal elements 56 which extend below the lower edge of the opening 42 so that the shells 50 will be forced to ride upwardly into the opening 42 and a concave face 5! adapted to engage the under part of the following shell to thereby retain the shells in their advanced position. The element 56 is biased to its upwardly pivoted position by a spring 56 carried on a base 59 which is removably attached to the base structure 26 of the unit by bolts 66. When the unit is changed around to receive shells from the opposite side of the same, this pawl mechanism 55 is removed from the base and is attached to the opposite side of the base structure 26.

To further convert the unit into an arrangement for receiving shells at the opposite side of the same, the cover plate 24 is removed after the bolts 25 are released. The plate 24 with the carrier 26 is simply turned about 180 sothat the carrier pin 66 is at the opposite side of the gun. This reversal of the plate 24 and the carrier 26 has been permitted by removing the pin and the bell crank pivot pin 29, The bell crank pivot pin 29 is moved to the opposite side of the plate 24 and inserted within an opening 6!. The bell crank 26 is re-mounted on the pivot pin 29 and the link 21 is re-connected to the bell crank 28. When the plate 24 is so reversed it takes with it the stripper elements 69 and 46 and thus they will automatically be aligned to receive the shell from the opposite direction. Through all of this transfer and change in the arrangement, the base structure 26 remains in its original position so that the shells are received within the opening 36, the same as before. If desired and more often the case, the unit can be removed from the gun and reassembled elsewhere.

By substituting for the link 27 a fluid motor or fluid link 62, Fig. 9, the feed unit can be operated "while the airplane is in the air to locate shell into opening 36, independently of the gun recoil mechanism. Referring now particularly to Fig. 10, it will be noted that this fluid unit 62 is connected to. a hydraulic supply system 63. This system is ordinarily provided on the airplane for operating a hydraulic charging cylinder 64, Fig. 4, on the gun. This charging cylinder 64 is such that a shell may be extracted from the gun at any time without the gun having to be fired to operate the recoil mechanism. By operating the fluid link 62. at the same time the charging cylinder 64 is operated, the shell in the gun is extracted and simultaneously the pawl carrier 20 is retracted (moved to the right in Fig. 9) until the pawls engage a following shell. At the end of its rearward stroke the fluid link 62 is returned to. its original. position by meansof a compression spring 69.

36. so that it is ready to be taken into the gun by the gun bolt, upon the bolt being returned by the charging cylinder. This fluid link is connected between the bell crank and the stud element I! in the same manner that the link 21 is connected. Upon the fluid link being contracted, an abutment 66 on its piston 61 will engage the end of its cylinder 68 so that the fluid link will have the same length as the link 21. The abutment 66 is retained in its engagement with the end of the cylinder 64 by a piston return spring 69 coiled about a piston rod 10.

Fluid for operating the fluid link is received from the system 63 through a threaded opening H so as to cause the piston 61 to be actuated to extend the piston rod 10 through a cylinder head 72 to operate the bell crank 28. The pawl carrier 26 will continue to be operated by the bell crank 28 so long as its pin 30 remains in the portion 33 of the over-travel slot 3|. When it falls over the ledge 34, further extension of the fluid link thereafter having no effect upon the pawl carrier.

This fluid system 63 includes a fluid pump pressure source 13 from which fluid is forced through a pipe 14 for delivery to a valve 15. This valve 75 is located in the cockpit of the airplane to be accessible to the pilot. When its handle 16 is in the position shown in full lines, fluid is delivered from the pipe 14 through the pipe [6 to both the fluid link 62 and the charging cylinder 64, the communication being made with the charging cylinder 64 from a T-connection l1 and through a pipe 78. When the link 62 and the charging cylinder 64 are finally filled or when the valve 15 is shut off, a bypass valve 19 is operated to automatically return the fluid from the pipe 14 to the pump source I3.

To extract the fluid from the fluid link 62 and the charging cylinder 64, the handle 16 is thrown to a position shown in dotted lines, and the fluid is returned through the same pipes in which the fluid was delivered from the valve 15 where it is diverted to a pipe 8! for its return to the pump source 13.

It should now be apparent that there has been provided a shell feed unit particularly adapted for automatic guns of a type mountable in airplane wings in which little head space above the gun is consumed by the unit, a unit which is reversible to receive the shells from either the right hand or left hand side of the unit, and one in which only minimum parts are required to provide for the functioning of the unit. It should also be apparent that the unit is such that shells can be fed through the unit while the airplane is in the air and that this feeding may be of any given amount and, if necessary, the full extent of W V This spring should be of suflicient strength W to advance the following shell into the opening belt without a single shell being It is also'apparent that the unit is completely fool proof in that it has no adjustable parts.

While various changes may be made in the detailed construction of the arrangement, it shall be understood that such changes shall be within the spirit and scope of the present invention as defined by the appended claims.

I claim as my invention:

1. In combination, an automatic gun having a recoil mechanism, a fluid pressure source, a shell feed unit on the gun for feeding shells to the same, said feed unit including shell advancing parts and means for connecting the parts to the gun recoil mechanism, said connecting means including a fluid expansible link whereby said advancing parts may be operated independently of the recoil mechanism and without the firing of the gun, and means for operatively connecting the fluid expansible link to the fluid pressure source to be operated by the same.

2. In combination, an automatic gun having a recoil mechanism, a shell feed unit on the gun for feeding shells to the same, said feed unit including shell advancing parts and means for connecting the parts to the gun recoil mechanism, said connecting means including an expansible link whereby said advancing parts may be operated independently of the recoil mechanism and without the firing of the gun, and control means for expanding said expansible linkn EDWARD J MEYER. 

